Now, it was a pretty big archive, probably around 100MB. And being a USB device, it didn't really all happen at once, so I left it running. The PowerBook was not connected to the mains, and, as far as I can see, it went to sleep in the middle of the archive extraction. When I woke the machine back up, the tar process was wedged hard. Control-C didn't work. Control-Z didn't work. kill didn't work. kill -KILL (inexplicably) didn't work. Nothing worked. So I got the Finder to terminate the shell. And as a side effect of something in this chain of events, the USB mass storage device terminated my data. Gone. Well, not quite: MacOS X wouldn't admit to seeing anything in the directory where the archive was, and wouldn't even give a directory listing. Windows XP saw the directory and the archive, but wouldn't read the latter. FreeBSD 5.3 saw everything, but, again, wouldn't read it.
Ultimately this was my fault.
- The data should have been moved off the USB stick months ago.
- I should never have been doing the extraction on the device itself.
- I should have had the PowerBook plugged into the mains if I was doing something important.